how to detect collision between two character controllers?

How is this done? I have 2 controllers, one tagged 'victim' the other 'player'

In scripts attached to the player controller the following fails: (and vice versa)

This does not work:

public void OnControllerColliderHit(ControllerColliderHit hit) { if (hit.controller.gameObject.tag == "victim") { //never gets here }

         if (hit.collider.tag == "victim")
 {
     //or here
 }

}

Neither does this:

public void OnCollisionEnter(Collision collision)
{
    // game logic never gets here
}

How do i detect this kind of thing?

Many thanks